Holder for flexible abrasive



Feb. 24, 1970 P.YC. BANNING firm. I 3,496,684

riowma FOR FLEXIBLE ABRASIVE Filed March 4.; 1968 I N VENTORS P5752 C. BAN/0N6 0 445. HUG-1.1.52

United States *at'ent 3,496,684 Patented Feb. 24, 1970 3,496,684 HOLDER FOR FLEXIBLE ABRASIVE Peter C. Banning, St. Joseph Township, St. Croix County,

Wis., and Dale W. Keller, Oakdale Township, Washington County, Minn., assignors to Minnesota Mining and Manufacturing Company, St. Paul, Minn., a corporation of Delaware Filed Mar. 4, 1968, Ser. No. 710,111 Int. Cl. B24d 9/02 U.S. Cl. 51-334 4 Claims ABSTRACT OF THE DISCLOSURE A furcate holder for flexible abrasive strips which permits efficient abrading of inside corners and internal surfaces of tubular articles. The holder, which is attachable to a rotary drive means, comprises a mounting shaft, an externally threaded body attached to one end of the shaft, a conical furcate abrasive gripping member having it base attached to one end of the body, and a threaded nut on the body which forces the furcate gripping jaws together as the nut is threaded toward the base of the conical member.

FIELD OF THE INVENTION This invention relates to holders for lofty flexible fibrous abrasives such as that described in U.S. Patent 2,958,593. More particularly, this invention relates to a holder for flexible abrasive sheets for grinding, deburring, and finishing material, such as metal, particularly for inside corners and internal surfaces of tubular articles.

Finishing devices and abrasive sheet holders such as those disclosed in U.S. Patents 2,516,870 and 2,522,613 have been known for some time but have not been entirely satisfactory with lofty flexible fibrous abrasives. Generally, these prior art devices do not securely grip the flexible abrasive, particularly when a small diameter device is used. Further, these prior art devices have not been useful in finishing inside corner areas with fibrous abrasives, largely because it has not been possible to securely hold the abrasive material near the front point or end of the holder. Further, it has been a slow cumbersome process to change abrasive, often necessitating removal of the holder from the drive chuck. It was also generally necessary to use only abrasive having a specific precut configuration.

SUMMARY OF THE INVENTION Our invention provides a holder for flexible abrasive which can be made of plastic and eliminates the problems associated with prior art devices. Our holder can be made in small sizes, and mounted on a small portable tool, to elfectively finish or polish the inside of small diameter pipe or other hollow or tubular articles. Additionally, our holder is so configured as to permit the flexible abrasive to generate a cone shape, making it possible to more readily finish small corner areas that heretofore could not be reached with lofty flexible fibrous abrasives. Our holder does not require the use of specific form or configuration of abrasive.

Our invention provides a single unit, one end of which can be releasably attached to a rotary drive means such as an electric drill. The other end of the holder has furcate jaws to receive the flexible abrasive, and has a not on the exterior surface of the center body portion to quickly and securely clamp the jaws and hold the abrasive in place. The abrasive material can be quickly and readily removed or changed without removing the holder from the drive means by merely unscrewing the clamping nut. The jaws are provided with teeth to securely 'hold the abrasive in place during rotation.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred form of our invention is illustrated in the accompanying drawing and will be more particularly described with reference thereto.

FIGURE 1 is a side elevational view of a holder in the closed position embodying the principles of our invention.

FIGURE 2 is a side elevational view of a holder showing the furcate jaws in the open position.

In the drawing, abrasive holder 10 which can be made of a tough durable plastic such as polyacetal comprises shaft 20, threaded slotted body member 30, conical furcate abrasive gripping member 40, and nut 50, the component parts all being operatively interconnected.

In the drawings, cylindrical mounting shaft 20 is adapted to be gripped by the chuck of a driving tool. While shaft 20 can be of any material, it is preferably of metal to provide strength and durability for high speed rotation. Shaft 20 is connected to threaded slotted body member 30 at joint 21 by means of ribs 22, with body member 30 having left-hand threads 31 on its external surface 32, so that nut will not loosen during high speed rotation. The diameter of body member 30 at shoulder 33 exceeds that of shaft 20. Body member 30 has a longitudinal slot 34 extending about one-half of its length, beginning at conical furcate abrasive gripping member base 41. Body member 30 is configured so that slot 34 and body member 30 are sprung slightly open near base 41, when in the open position. Threading nut 50 toward base 41 closes slot 34 and causes body member 30 to become cylindrical.

The forward end of body member 30' is connected to conical furcate abrasive gripping member 40 at its base 41 with slot 34 extending throughout the length of gripping member 40 to define jaws 42 with lips 45. Jaws 42 grip fibrous abrasive sheets and provide easy access to small difficult to reach areas. The diameter of base 41 exceeds that of body member 30. If desired, a plurality of slots may be used to define a plurality of furculae to create more than two jaws. Inner surfaces 43 of jaws 42 have a plurality of inwardly projecting teeth 44 to securely hold the flexible abrasive sheets in place during high speed revolution.

Furcate abrasive gripping member 40 is conical to permit abrasive material to wrap around its exterior surface when rotated at high speed thereby forming a tapered tool for abrading in small areas. Nut 50 is provided with threads adapted to mate with threads 31 of body member 30 so that when nut 50 is threaded along slotted body member 30, toward base 41, jaws 42 are forced together to securely grip the abrasive material. Although not critical to effective operation, nut 50 has the same conical taper as gripping member 40 so that when threaded against base 41, a continuous cone is formed comprising holder 40 and nut '50. The small 3 4 a cylindrical mounting shaft, adapted to be gripped ing shaft is metal and the remainder of the holder is by the chuck of a driving tool, a tough durable plastic. an externally threaded slotted body member attached 4. The holder of claim 3 wherein the nut has the to said shaft at one end thereof, the diameter of same conical taper as the abrasive gripping member.

said body exceeding that of said shaft,

a conical furcate abrasive gripping member connected eferen s Cited to one end of said body, the base of said conical UNITED STATES PATENTS gripping member being connected to said body, hav- N k 724,475 4/1903 Hilno 27942 m a diameter larger than sa1d body, with aw 1,082,617 12/1913 Anton defining furculae extending into said. body, and

a nut adapted to mate with the external thread of 10 6/1918 Spauldmg 27942 said body, the jaws of the abrasive gripping member 15 10/1924 FOX 24 260 being forced together as said nut is threaded on 6/1968 287M115 X said body member toward the base of said conica gripping member. I l 15 OTHELL M. SIMPSON, Prlmary Examiner 2. The holder of clalm 1 whereln the abrasive grlp- US. Cl. X.R.

ping member is bifurcate. 51364; 27942 3. The holder of claim 2 wherein the cylindrical mount- 

